1. Colour coding
Colour coding must be used on the shoulder at the valve end for the identification of the contents. In compliance with standard SFS-EN 1089-3, the colour codes for air content are white and black. Colour coding may also be located on the protective cap on the shoulder at the valve end.
For safety reasons, the colour of the cylinder must be yellow in order to ensure that the bottle is visible. Alternatively, a yellow protective sleeve may be used if the bottle itself is the colour of the composite material. However, the protective sleeve must not compromise the safety of smoke diving.
The painting of composite bottles is not recommended unless this is permitted in the manufacturer and importer's instructions. A painted surface can disguise damage and solvents used in the paint could damage the composite material.
2. Limited lifetime
For certain composite bottle types, the service life is limited to 15 years. The lifetime of the oldest existing bottles, manufactured in the early 1990s, has expired. When its lifetime has expired, a cylinder must not be used even if it is still in good condition and could, therefore, pass the periodic inspection.
The limited lifetime is indicated on the bottles, e.g. by the code “FIN” and the year and month of expiry (two digits, respectively). For example, if the lifetime expired in August 2006, the code is FIN 06/08.
The code for an unlimited lifetime is e.g. NLL.
Composite bottles are light and strong but must be handled with care in storage, when in use, and during maintenance. Any damage due to impacts such as cuts, cracking and delamination pose a risk to pressure strength. Such damage may result in the rejection of the bottle during a periodic inspection.
In every case, the external condition of the bottle and valve must be checked after use and before filling.
Composite bottles must be serviced at regular intervals, in accordance with the manufacturer's and importer's instructions. The external and internal surfaces of the bottle must be cleaned during maintenance. All stains and loose paint must be removed from the external surface, and all stains and any corroded points cleaned off the internal surface. No chemical cleaning agents or solvents may be used in cleaning, unless this is specifically permitted in the instructions.
The condition of the external and internal surface of the bottle, and the valve connection, must be checked for potential damage. Should any damage be detected during an inspection, the related risks must be determined alongside the manufacturer and importer and the inspection body.
External damage can include abrasions, cuts, grooves, cracking, delamination, including loose fibre ends, discolouration and blisters, marks caused by heat or flames, bulges and indentations, dissolution due to chemicals, or deformation of the valve connector.
Damage to the internal surface can include corrosion, depressions and cracking. Bottles with a plastic liner, or bottles manufactured without one, may show signs of damage caused by heat, e.g. due to being filled too rapidly.
The external condition of the valve must be inspected. If the valve body, handwheel, spindle or threads are damaged, the valve must be replaced. Maintenance of the valve must include general cleaning and the replacement of seals and worn components. If any seals or lubricants are used, they must be compatible with breathing air. After the valve has been re-assembled, it must be checked for leaks and correct operation. This may be done prior to the valve being refitted, or afterwards during the first filling subsequent to installation.
The valve must be detached and installed using the tools and methods appropriate for such a purpose. If the valve connector has grooves (width across flats) for a wrench, a wrench must be used when detaching and re-installing the valve. The bottle may not be tightened or squeezed by holding the cylinder. The sealing and tightening torque of the valve installation must comply with the instructions in question.
5. Periodic inspections
Statutory periodic inspections of composite bottles must be performed by an inspection body at three-year intervals. A periodic inspection includes the following measures:
- inspection of the code labels on the bottle and valve
- inspection of the external and internal condition of the bottle (see point 4 above)
- hydrostatic pressure test of the bottle; the hydrostatic test pressure must be 1.5 times the maximum permitted filling pressure (to be performed as volumetric expansion test if the manufacturer's and importer's instructions so require)
- inspection of the functioning and tightness of the bottle valve (see point 4 above)
- labelling of the bottle with test markings.
The bottle and valve must be prepared for the periodic inspection (see point 4 above). The inspection must comply with the manufacturer's and importer's instructions. Moreover, the standard SFS-EN ISO 11623, instructions for the periodic inspection and testing of composite gas cylinders, may be applied during the inspection. However, when applying the standard, it should be noted that the manufacturer's and importer's instructions may include stricter requirements.
Johanna Soppela, Senior Inspector, tel. +358 29 5052 585, e-mail: email@example.com